Over the last four years, we have created a broad, interdisciplinary research program dedicated to exploring basic and clinical aspects of fungi that cause lifethreatening, systemic infections in humans. Our activities have been, and will continue to be, centered on the fungal opportunists, exemplified by species of Cryptococcus, Candida, Aspergillus, Mucor, and Rhizopus. Such organisms are frequently responsible for illness and death among patients with underlying malignant or immunologically mediated diseases. At UCLA, they are especially prevalent among patients with hematologic malignancies and/or recipients of bone marrow transplants (see documentation within the proposal). In addition, UCLA has become a referral center for patients with AIDS. Such patients frequently have esophageal candidiasis and are threatened by Aspergillus spp. and Cryptococcus neoformans. Our long-term goals and research objectives, and the specific methodology we will apply to attain them are described comprehensively in the six interrelated proposals that comprise our overall program. Our collaborative research program coordinates the efforts of established scientists in neighboring institutions around the large and diverse patient population based at UCLA. By so doing, we will facilitate the transfer of anticipated advances in basic mycology, immunology, epidemiology, immunodiagnosis, and developmental and applied therapeutics to patients afflicted with severe fungal infections.